Tag Archives: Browning Machine Gun Caliber .50 AN-M2

1 September 1946

September 1, 2023Aviation37 mm Aircraft Gun M4, 42-20869, Aeroproducts Division of General Motors Corporation, Allegheny-Ludlum Trophy, Allison Division of General Motors, Allison Engineering Co. V-1710-135, Allison V-1710-E31, Alvin Melvin Johnston, Bell Aircraft Corporation, Bell Model 26Q-10, Bell P-39Q-10-BE Airacobra, Browning Machine Gun Caliber .50 AN-M2, c/n 26E-324, Cobra II, N9284, NX92848, Tex Johnston, Thompson Trophy, VoughtBryan Swopes

Johnston, Alvin Melvin ("Tex"), with the Thompson Trophy and the Allegheny-Ludlum Trophy, and his Bell P-39Q Airacobra, NX92848, Cobra II. (San Diego Air and Space Museum Archives Catalog # 15-00809) — Alvin M. “Tex” Johnston with the Thompson Trophy and the Allegheny-Ludlum Trophy, 1946 National Air Races. (San Diego Air and Space Museum Archives)

1 September 1946: Just one year after World War II came to an end, the National Air Races returned to Cleveland, Ohio. Grandstands were set up at the site of the Fisher Body Aircraft Plant No. 2, where assemblies for B-25 and B-29 bombers had been produced.

The Thompson Trophy Race was one of the most popular events because it was in view of the crowds. Sponsored by Thompson Products Company (the predecessor of TRW), it was a ten-lap pylon race flown at low altitude around a 30-mile (48.3 kilometers) course. There were two divisions. The R Division was for airplanes with reciprocating engines, and the J Division was for turbojet powered airplanes.

The National Air Races 4-pylon course, flown in 1946, 1947 and 1948. (airrace.com)

The race course was laid out as a parallelogram, with two 10-mile (16.1 kilometer) sides, and two 5-mile (8.0 kilometer) sides. There were two 75° turns and two 105° turns.

In addition to the Thompson Trophy, the race winner would receive $20,000 in prize money (about $342,400 in 2018 U.S. dollars). There were additional $2,000 prizes for the leader of each lap. A pilot who set a speed record during the race would win the Allegheny-Ludlum Trophy and $2,000.

Entrants for the 1946 race included many well-known air racers, test pilots and combat pilots. They included Cook Cleland, a U.S. Navy dive bomber pilot and test pilot; Woodrow W. (“Woody”) Edmondson, an aerobatic pilot; Howard Clifton (“Tick”) Lilly, a test pilot for the National Advisory Committee for Aeronautics (NACA, predecessor of NASA); Alvin Melvin (“Tex”) Johnston, an experimental test pilot with the Bell Aircraft Corporation; Anthony W. (“Tony”) LeVier, Chief Engineering Test Pilot for the Lockheed Aircraft Corporation, and an experienced pylon racer; Earl Hill Ortman, test pilot for Douglas Aircraft Company, and also an experienced racer; Howard L. Pemberton; Bruce Raymond; Robert Swanson; Charles (“Chuck”) Tucker, who had flown P-40s with the “Flying Tigers” in China, and an Army Air Corps test pilot; George Schwarz Welch, the Army Air Corps hero of Pearl Harbor, and test pilot for North American Aviation, Inc.; and Sylvester Joseph (“Steve”) Wittman, an aircraft designer and air racer.

Before the war, the races used specially-constructed racing aircraft and production civil aircraft. Following the war, the expense of developing a purpose-built, competitive air racer was no longer feasible, so surplus military fighters were used.

Of the twelve airplanes competing in the 1946 Thompson Race, there was one Bell Aircraft Corporation P-39Q Airacobra; four Bell P-63 Kingcobras; one Goodyear Aircraft Corporation FG-1D Corsair (a licensed variant of the Vought-Sikorsky F4U Corsair); a Lockheed Aircraft Corporation P-38L Lightning; and five North American Aviation, Inc., P-51D Mustangs.

Jack Woolams, Chief Test Pilot for Bell Aircraft Corporation, Experimental Test Pilot Tex Johnston, and Bell’s Chief Engineer, Robert Morris Stanley, had determined that a properly prepared Bell P-39 Airacobra could outrun and outfly a North American Aviation P-51 Mustang in the Thompson race.

A Bell Aircraft mechanic was sent to inspect surplus P-39s in storage at Ponca City, Oklahoma. He selected two nearly-new P-39Q Airacobras, each with less than 50 hours flight time. Woolams and Johnston paid $3,000 for the two fighters and they were flown back to the Bell plant at Buffalo, New York.

Jack Woolams’ Cobra I was a P-39Q-10-BE, U.S. Army Air Corps serial number 42-20733. Tex Johnston’s Cobra II was also a P-39Q-10-BE, 42-20869 (Bell serial number 26E-324).

The Bell P-39 Airacobra was a single-engine, single-place low-wing monoplane with retractable tricycle landing gear. An Allison V-1710 V-12 engine was mounted behind the cockpit in an unusual mid-engine configuration, with a drive shaft passing under the cockpit floor and turning the propeller through a remotely-mounted 1.8:1 gear reduction unit. This allowed the fighter to be armed with a large 37 mm autocannon which fired through the propeller hub.

Bell P-39Q-20-BE Airacobra 44-3887 at the National Museum of the United States Air Force. (United States Air Force 050215-F-1234P-062)) — Bell P-39Q-20-BE Airacobra 44-3887 at the National Museum of the United States Air Force)

The P-39Q was the final production version of the Airacobra. It was 30 feet, 2 inches (9.195 meters) long with a wingspan of 34 feet, 0 inches (10.363 meters) overall height of 12 feet, 5 inches (3.785 meters). The wings’ angle of incidence was +2° and there was 4° 0′ dihedral. The total wing area was 213 square feet (19.78 square meters). The horizontal stabilizer had +2° 15′ incidence and no dihedral. The P-39Q had an empty weight of 5,692 pounds (2,704 kilograms), and maximum gross weight of 8,350 pounds (3,787 kilograms).

The production P-39Q was powered by a liquid-cooled, supercharged, 1,710.597-cubic-inch-displacement (28.032 liter) Allison Engineering Company V-1710-E19 (V-1710-85) single overhead camshaft (SOHC) 60° V-12 engine with four valves per cylinder and a compression ratio of 6.65:1. The V-1710-85 had a continuous power rating of 810 horsepower at 2,600 r.p.m. at Sea Level, and 1,000 horsepower at 2,600 r.p.m. at 14,000 feet (4,267 meters). The engine’s takeoff power rating was 1,200 horsepower at 3,000 r.p.m., and its military power rating was 1,125 horsepower at 3,000 r.p.m., at 14,600 feet (4,450 meters). 100/130 octane aviation gasoline was required. The Allison drove a three-bladed Aeroproducts Division A632S-C1 hydraulically-operated constant-speed propeller with a diameter of 11 feet, 7 inches (3.531 meters) through a 2.23:1 gear reduction. The V-1710-85 was 16 feet, 2.00 inches (4.928 meters) long, 3 feet, 1.56 inches (0.954 meters) high, and 2 feet, 5.28 inches (0.744 meters) wide. It weighed 1,435 pounds (651 kilograms).

Cutaway illustration showing the unusual mid-engine arrangement of the Bell P-39 Airacobra. (Allison Division of General Motors)

The Bell P39Q-10-BE had a maximum speed of 385.0 mph (619.6 kilometers per hour) at 11,000 feet (3,353 meters). Its service ceiling was 34,300 feet (10,455 meters), absolute ceiling, 35,700 feet (10,881 meters), and its range was 1,075 miles (1,730 kilometers).

The P-39Q was armed with one Browning M4 37 mm autocannon with 30 rounds of explosive ammunition, and four Browning AN-M2 .50-caliber machine guns, with two in the nose with 200 rounds per gun, and one mounted under each wing in pods with 300 rounds per gun. The M4 cannon fired a 1.34 pound (608 grams) high-explosive shell at 2,000 feet per second (610 meters per second). The gun had a rate of fire of 150 rounds per minute.

The Bell Aircraft Corporation built 9,558 P-39s. 4,905 of these were P-39Qs. 705 were the P-39Q-10-BE variant.

Jack Woolams (left) and Tex Johnston pose with their air racers, Cobra I and Cobra II, at the Bell Aircraft Corporation plant, August 1946. (airrace,com)

Bell Aircraft provided hangar space for the two Airacobras, and assigned an engineer and five mechanics to the project. Cobra I was painted red with black accents. It was issued Civil Aeronautics Administration experimental registration NX92847. Its race number, 75, was painted on the wings and fuselage. Cobra II was painted yellow with black trim, and registered NX92848. Its race number was 84.

Both airplanes were stripped of armament, armor and self-sealing fuel tanks. The landing gear was modified to reduce its retraction time from 22 seconds to just 4 seconds. The standard fabric-covered ailerons, rudder and elevators were covered with sheet aluminum. Adjustable trim tabs were deleted. Gyroscopic instruments were removed. The pitot tube was moved from the left wing tip and placed on a long boom projecting through the propeller hub. Thin, light-weight Goodyear fuel bladders were installed, not only reducing weight, but increasing the Airacobras’ fuel capacity by 10%. The roll-down side windows of the P-39 were replaced by fixed Plexiglas panels.

Bell P-39Q-10-BE NX92848, Cobra II, Tex Johnston’s Thompson Trophy Race winner. (San Diego Air and Space Museum Archives)

Engineers at Allison recommended that a modified Allison XV-1710-135 (E31) engine be used for the two racers. The modified engines used an increased-diameter supercharger impeller and undersized pistons to reduce cylinder wall friction. Using 140-octane Mobil aviation gasoline, they produced 2,000 horsepower at 3,200 r.p.m. with 86 inches (291 kilopascals) of manifold pressure. The high power output required that the engine be provided with a continuous injection of a precisely-measured water and ethyl/methyl alcohol solution when operating above 57 inches (193 kilopascals) of manifold pressure. An 85 gallon (322 liter) tank for the injection mixture was placed in the nose.

Tex Johnston’s Thompson Trophy-winning Bell P39Q Airacobra, “Cobra II.” (San Diego Air and Space Museum Archives)

The increased power of the modified XV-1710-135 required that the P-39’s standard three-bladed propeller be replaced by a four-bladed unit from the P-63 Kingcobra. This was an Aeroproducts A624S constant-speed propeller with hollow steel blades. Its diameter was 11 feet, 0 inches (3.531 meters). The propeller gear reduction ratio remained the same, at 2.23:1, as did the remote gear box, at 1.8:1.

Allison V-1710-E19 (V-1710-85) with extension drive shaft and remote propeller drive gear unit. (Allison Division of General Motors)

The V-1710-E31 was longer and heavier than the -E19 because of an outboard reduction gear box. It was 17 feet, 4.00 inches (5.283 meters) long, 3 feet, 0.75 inches (0.933 meters) high, with the same 2 foot, 5.28 inch (0.744 meters) width. It weighed 1,500 pounds (680 kilograms).

Jack Woolams’ P-39 Cobra I leads a P-51D Mustang around a pylon turn during qualifying, August 1946. (LIFE Magazine via Jet Pilot Overseas)

When race qualifications were held, Tex Johnston was placed first with his yellow Cobra II. His average speed was 409.091 mph (658.368 kilometers per hour). George Welch was second with his P-51D, number 37. Jack Woolams and Cobra I were third.

Jack Valentine Woolams, Chief Experimental Test Pilot, Bell Aircraft Corporation. (John Trudell/Ancestry)

Jack Valentine Woolams was killed on 30 August, two days before the race, when his Cobra I crashed into Lake Ontario while returning to the Bell plant for an engine change. The Airacobra’s windshield may have collapsed at over 400 miles per hour (644 kilometers per hour).

The Thompson Trophy Race was held on Sunday, 1 September 1946. Tex Johnston, leading the field, took off and retracted his landing gear, climbing to 300 feet (91 meters). As he approached the first turn, he rolled Cobra II into a 4G turn (75.5° angle of bank) and dove to 60 feet (18 meters). As he made the turn, he was already pulling far ahead of the other racers.

George Welch dropped out when his Merlin engine began overheating. Tony LeVier’s P-38 Lightning, race number 3, held on to second place. By the ninth lap, Tex Johnston was passing the airplanes at the back of the field.

On the final turn, Johnston rolled into a 90° bank, and at only 50 feet (15 meters) above the ground, passed inside a Bell P-63 Kingcobra at 430 miles per hour (692 kilometers per hour) to win the race. His average speed for the ten laps was 373.908 mph (601.746 kilometers per hour).

After winning the 1946 Thompson Trophy Race, test pilot Tex Johnston kisses his wife, DeLores. (LIFE Magazine via Jet Pilot Overseas.)

Johnston, Alvin Melvin ("Tex"), Bell Aircraft Corporation experimental test pilot, with the Thompson Trophy, at the National Air Races, Cleveland, Ohio, 1 September 1946. (LIFE Magazine) — Tex Johnston with the Thompson Trophy, 1946 National Air Races, Cleveland, Ohio. (LIFE Magazine)

Tony LeVier and his Lightning were in second place at 370.193 mph (595.768 kilometers per hour). Finishers 3, 4 and 5 were P-51D Mustangs. Number 6 was the lone FG-1D Corsair, followed by another P-51D. Proving that Woolams, Johnston and Stanley knew their airplane, the final three finishers were the three remaining P-63 Kingcobras.

Bell P-39Q-10-BE Airacobra NX92848, Cobra II, "Tex" Johnston's 1946 Thompson Trophy Race winner, at Cleveland 1946, left rear quarter view (San Diego Air and Space Museum Archives Catalog # 15_002120) — An oil-streaked, race-winning Bell P-39Q Airacobra, NX92848, Tex Johnston’s Cobra II. The modified Allison engine’s undersized pistons allowed excessive blow-by. (San Diego Air and Space Museum Archives)

Cobra II competed in the 1947 Thompson Trophy Race. Flown by Bell Aircraft Corp. test pilot Gerald A. (“Jay”) Demming, and carrying the race number 11, it finished in third place behind two Goodyear F2G-1 Super Corsairs. Demming’s average speed was 367.625 miles per hour (591.635 kilometers per hour).

In the 1948 Thompson race, Cobra II, still carrying the number 11, was flown by Charles Brown. For this year, the race was twenty laps of a shorter, 15 mile (24.1 kilometer) course. Cobra II had qualified in first place with an average speed of 418.300 miles per hour (673.189 kilometers per hour). Brown led the race for 18 laps. His highest speed for a single lap was 413.907 miles per hour (666.119 kilometers per hour). He had to land, though, when the modified Allison engine began losing power. The race was won by a P-51D Mustang.

Bell P-39Q-10-BE Airacobra NX92849 — Cobra II at the 1947 National Air Races, with race number 11. It was flown in the Thompson Trophy race by Bell test pilot Jay Demming, who placed third. (SDASM)

The history of Cobra II is elusive until it was purchased by Ed Maloney in 1960. It was sold to Michael D. Carroll in 1967. Carroll was the owner of Signal Trucking Co., and lived in Palos Verdes, California. The Airacobra was now registered N9824. Carroll had the airplane’s wings shortened by 4 feet per side (1.2 meters), and renamed it Cobra III.

On 10 August 1968, Carroll and Cobra III took of from Long Beach Airport (LGB), enroute to Orange County Airport (SNA), at nearby Santa Ana, California. At 11:15 a.m., the racer crashed at the Seal Beach Naval Weapons Station. Carroll bailed out, but his parachute did not open and he was killed. His body was located 125 feet (38 meters) from the wreckage. There was no post-crash fire. Lieutenant Commander Jack Kellicott, U.S. Navy, said that the airplane had run out of fuel.

Tex Johnston left Bell Aircraft Corporation and moved on to Boeing in Seattle, initially testing the swept-wing XB-47 Stratojet. He made the first flights of the YB-52 and XB-52 Stratofortress; the Model 367-80 (the “Dash 80”), which he notoriously rolled over Lake Washington, 6 August 1955; the KC-135A Stratotanker; and the Model 707 airliner. As Boeing’s Chief of Flight Test, Tex Johnston set the standard by which modern flight testing is carried out.

Alvin Melvin (“Tex”) Johnston, Chief of Flight Test. (The Boeing Company)

Highly recommended: Tex Johnston, Jet-Age Test Pilot, by A.M. “Tex” Johnston with Charles Barton, Smithsonian Books, Washington, D.C., 1991

21 August 1944

August 21, 2023Aviation20 mm Aircraft Automatic Gun M3, Aeroproducts Propeller Company, Browning Machine Gun Caliber .50 AN-M2, Bu. No. 90460, Fighter, First Flight, Grumman Aircraft Engineering Corporation, Grumman G-58, Grumman XF8F-1 Bearcat, Pratt & Whitney Double Wasp 2SC13-G, Pratt & Whitney R-2800-22, Prototype, Robert Leicester HallBryan Swopes

Robert L. Hall in the cockpit of the prototype Grumman XF8F-1 Bearcat. (Northrop Grumman)

21 August 1944:¹ The first of two Grumman XF8F-1 Bearcat prototypes, Bu. No. 90460, made its first flight at Bethpage, New York, with Grumman’s Chief Engineer and test pilot Robert Leicester Hall at the controls. The Bearcat was a light-weight high performance interceptor, designed to operate from the U.S. Navy’s smaller aircraft carriers. It used an air-cooled, supercharged, 2,804.4-cubic-inch-displacement (45.956 liter) Pratt & Whitney Double Wasp 2SC13-G (R-2800-22) two-row, 18-cylinder radial engine, an uprated version of the engine used in its predecessor, the Grumman F6F Hellcat.

The R-2800-22 engine was rated at 1,700 horsepower at 2,600 r.p.m. at Sea Level, and 2,100 horsepower at 2,800 r.p.m., for takeoff and Military Power. In order to use the engine’s power more effectively, the prototype Bearcat used a 12-foot, 4-inch (3.759 meter) diameter, four-bladed Aero Products, Inc., propeller, driven through a 0.45:1 gear reduction.

Prototype Grumman XF8F-1 Bearcat. (Northrop Grumman)

The Bearcat was 20% lighter than the Hellcat. It was 50 miles per hour faster and had a much higher rate of climb.

For aircraft carrier operations, the new fighter could not sacrifice structural strength. In order to limit the weight, armament was reduced to four .50-caliber machine guns, and fuel capacity was also less than that of the Hellcat, giving it reduced range.

Grumman F8F-1 Bearcat with wings folded. (U.S. Navy) — Grumman F8F-1 Bearcat with wings folded, 20 March 1945. (Northrop Grumman)

The production F8F-1 Bearcat was 27 feet, 6 inches (8.382 meters) long with a wingspan of 35 feet, 6 inches (10.820 meters) and overall height of 13 feet, 10 inches (4.216 meters) (to tip of propeller, in three-point position). With its wings folded, the width of the Bearcat was reduced to 23 feet, 9½ inches (7.252 meters).

The Bearcat’s wings are sharply tapered. Their angle of incidence is −1½°, and there is 5° 30′ dihedral. The leading edges are swept aft 5° 5′. The chord decreases from 9 feet, 7.87 inches (2.943 meters) at the root to 4 feet, 3.5 inches (1.308 meters) at a point 6 inches (15.24 centimeters) inboard from the tip. The total wing area is 244 square feet (22.7 square meters).

The fighter’s horizontal stabilizer has a span of 15 feet, 9 inches (4.801 meters) and a total area of 52.2 square feet (4.85 square meters). Its angle of incidence is +½°. The rudder has a height of 6 feet, 1–13/16 inches (1.875 meters). The vertical tail has a total area of 20.8 square feet (1.93 square meters), and is offset 2° left.

The F8F-1’s empty weight was 7,070 pounds (3,207 kilograms) and maximum takeoff weight was 12,947 pounds (5,873 kilograms). The F8F-2’s empty weight increased to 7,650 pounds (3,470 kilograms), and its maximum takeoff weight was 13,460 pounds (6,105 kilograms).

Grumman XF8F-1 Bearcat prototype at NACA Langley Memorial Aeronautical Laboratory, Hampton, Virginia, 5 February 1945. (National Aeronautics and Space Administration LAML 42397) — Grumman XF8F-1 Bearcat prototype at NACA Langley Memorial Aeronautical Laboratory, Hampton, Virginia, 5 February 1945. (NASA)

The production F8F-1 was powered by a Pratt & Whitney Double Wasp 2SC14-G (R-2800-34W) engine which had the same Sea Level power ratings as the R-2800-22. It produced 1,500 horsepower at 2,600 r.p.m. at 18,500 feet (5,639 meters) and had a Military Power rating of 1,700 horsepower at 2,800 r.p.m. at 16,000 feet (4,877 meters). The gear reduction drive ratio was also 0.45:1. A slightly larger Aero Products propeller with a diameter of 12 feet, 7 inches (5.835 meters) was installed. The R-2800-34W was 6 feet, 2.134 inches (1.883 meters) long, 4 feet, 4.80 inches (1.341 meters) in diameter and weighed 2,358.5 pounds (1,069.8 kilograms).

The F8F-2 was powered by a Pratt & Whitney R-2800-30W. The Normal Power rating increased to 1,720 horsepower at 2,600 r.p.m. at Sea Level, and 1,450 horsepower at 22,000 feet (6,706 meters). Takeoff and Military Power also increased: 2,250 horsepower at 2,800 r.p.m. at Sea Level, and 1,600 horsepower at 22,000 feet (6,706 meters). The R-2800-30W also drove an Aero Products propeller. The gear reduction ratio was the same. Its dimensions were slightly different than the -34W: 7 feet, 8.75 inches (2.356 meters) long, and 4 feet, 5.00 inches (1.346 meters) in diameter. The engine’s weight increased to 2,560 pounds (1,161 kilograms).

Grumman F8F-1 Bearcat Bu. No. 90448 in the Full Scale Tunnel at NACA Langley Memorial Aeronautical Laboratory. (NASA EL-2003-00320)

The Bearcat had a top speed of 336 knots (387 miles per hour/622 kilometers per hour) at Sea Level, and 388 knots (447 miles per hour/719 kilometers per hour) at 28,000 feet (8,534 meters). The airplane had initial rate of climb at Sea Level of 4,465 feet per minute (22.68 meters per second) and it could climb to 20,000 feet (6,096 meters) in 8.4 minutes. Its ceiling was 38,200 feet (11,643 meters).

Fuel capacity is 185 U.S. gallons (700 liters). The fighter’s range could be extended with a jettisonable centerline and two underwing tanks. The Bearcat’s combat radius was 235 nautical miles (270 statute miles/435 kilometers). Its maximum range, with three external tanks (350 gallons/1,325 liters), was 1,595 nautical miles (1,835 statute miles/2,954 kilometers).

The F8F-1 Bearcat was armed with four Browning AN-M2 .50-caliber machine guns. Inboard guns were provided with 325 rounds of ammunition, each, while the outboard guns had 200 rounds per gun. The F8F-2 replaced these with four M3 20 mm autocannon. Each inboard cannon had 325 rounds per gun, and the outboard guns had 188 rounds each. The F8F could also be armed with up to three 11.75-inch (29.845 centimeters) Tiny Tim air-to-ground rockets, or four 5-inch (12.7 centimeter) High Velocity Aerial Rockets (HVAR). For bombing missions, the Bearcat could carry one 1,600 pound (726 kilograms) bomb on the centerline and two 1,000 pounders (454 kilograms, each) under the wings.

The first prototype Grumman XF8F-1 Bearcat, Bu. No. 90460, crashed into Chesapeake Bay during gunnery tests at NAS Patuxent River, Maryland, 18 March 1945. Its pilot was missing, presumably killed. The airplane has recently–probably—been located.²

Multi-beam echo image of the aircraft at the bottom of the Chesapeake Bay believed to be the XF8F-1 Bearcat lost out of NAS Patuxent River March 18, 1945. (National Oceanic and Atmospheric Administration) — “Multi-beam echo image of the aircraft at the bottom of the Chesapeake Bay believed to be the XF8F-1 Bearcat lost out of NAS Patuxent River March 18, 1945.” (NOAA/Naval Aviation News)

Between 1945 and 1949, Grumman produced 1,265 F8F Bearcats, including a civilian G-58A and a G-58B. A number of American test pilots and astronauts flew the Bearcat in naval service, and several, including Neil Armstong, described it as their all-time favorite airplane.

Grumman F8F bearcat fighters aboard the Essex-class aircraft carrier, USS Tarawa (CV-40) circa 1948. (U.S. Navy) — Grumman F8F Bearcat fighters ready for takeoff aboard the *Essex*-class aircraft carrier, *USS Tarawa* (CV-40) circa 1948. (U.S. Navy)

Robert Leicester Hall was born at Taunton, Massachussetts, 22 August 1905. He was the son of Bicknell Hall, a mechanical engineer, and Estella Beatrice Lane Hall.

Hall attended the University of Michigan, graduating in 1927 with Bachelor of Science degree in Mechanical Engineering (B.S.M.E.). He was a member of the Phi Gamma Delta (ΦΓΔ) fraternity and the glee club. While at the University, Hall became a member of the American Society of Mechanical Engineers.

In 1929 he went to work for the Fairchild Airplane Manufacturing Company at Farmingdale, New York. While there, Hall met his first wife, Eugenie Therese Zeller, a 1928 graduate of Cornell University, and a secretary at the plant. They were married in 1930, and lived in a rented home on St. James Avenue, Chicopee City, Massachusetts. Their son, Robert Jr., was born 5 November 1931. They later divorced.

Also in 1931, Hall began working for Granville Brothers Aircraft at Springfield, Massachusetts. He designed the Gee Bee Model Z Super Sportster air racer. He left Granville Brothers in 1933 to go to work for the Stinson Aircraft Company in Dayton, Ohio. There he designed the Stinson Reliant.

In 1936, Bob Hall became the Chief Engineer for the Grumman Aircraft Engineering Corporation, Bethpage, Long Island, New York. He designed the F4F Wildcat, F6F Hellcat, F7F Tigercat, and F8F Bearcat fighters, and the TBF Avenger torpedo bomber. As corporate vice president, he supervised the design of the F9F Panther and Cougar jet fighters.

A U.S. Navy Grumman F4F-3 Wildcat in non-specular blue-gray over light-gray scheme in early 1942. (U.S. Navy)

Two Grumman F6F-3 Hellcat fighters, Summer 1943. (U.S. Navy)

Grumman TBF Avenger torpedo bomber. (U.S. Navy)

Ensign Neil A. Armstrong, as wingman to Lieutenant (j.g.) Ernie Moore, is flying the second Grumman F9F-2 Panther, Bu. No. 125122 (marked S 116), assigned to VF-51, USS Essex (CV-9), 1951. (Naval Aviation Museum)

Hall married his second wife, Rhoda C. Halvorsen, 18 January 1939, at New York City, New York.

Robert Hall retired from Grumman in 1970. Two of his sons, Eric and Ben Hall, founded Hall Spars and Rigging of Bristol, Rhode Island.

Robert Leicester Hall died at Newport, Rhode Island, 25 February 1991 at the age of 85 years.

¹ Some sources give 31 August 1944 as the date of the first flight.

² Naval Aviation News, 31 August 2017:

http://navalaviationnews.navylive.dodlive.mil/2017/08/31/lost-bearcat-found-or-still-missing/

19 August 1940

August 19, 2023Aviation40-2165, Browning Aircraft Machine Gun Caliber .30 M2, Browning Machine Gun Caliber .50 AN-M2, c/n 62-2834, First Flight, Medium Bomber, Mines Field, North American Aviation B-25 Mitchell, North American Aviation Inc., North American Aviation Model NA-62, Roy Ferren, Test Pilot, Vance Breese, Wright Aeronautical Division, Wright Cyclone 14 GR2600B665, Wright R-2600-9Bryan Swopes

19 August 1940: At Mines Field (now known as Los Angeles International Airport), the first North American Aviation B-25 twin-engine medium bomber, serial number 40-2165, took off on its first flight with test pilot Vance Breese at the controls and engineer Roy Ferren in the co-pilot’s position.

The airplane, North American model NA-62, serial number 62-2834, was developed from two earlier designs which had been evaluated by the U.S. Air Corps but rejected, and it was ordered into production without a prototype being built.

The first few B-25s built—sources vary, but 8–10 airplanes—were built with a constant dihedral wing. Testing at Wright Field showed that the airplane had a slight tendency to “Dutch roll” so all B-25s after those were built with a “cranked” wing, with the outer wing panels having very slight dihedral ¹ and giving it the bomber’s characteristic “gull wing” appearance. The two vertical stabilizers were also increased in size.

40-2165 was retained by North American for testing while the next several aircraft were sent to Wright Field.

The B-25 was named Mitchell in honor of early air power advocate Brigadier General Billy Mitchell. A total of 9,984 B-25s, F-10 reconnaissance variants and U.S. Navy and Marine Corps PBJ-1 patrol bombers were built by North American Aviation at Inglewood, California and Kansas City, Kansas. The last one, a TB-25J, remained in service with the U.S. Air Force until 1960.

Twenty-three B-25s were built before the B-25A Mitchell went into production. The B-25 was operated by a crew of five. It was 54 feet, 1 inch (16.485 meters) long with a wingspan of 67 feet, 6.7 inches (20.592 meters) and overall height of 16 feet, 4 inches (4.978 meters). The empty weight was 17,258 pounds (7,828 kilograms) and the maximum gross weight was 28,557 pounds (12,953 kilograms).

Scale model of a North American Aviation B-25 medium bomber being tested in a wind tunnel. (4″ × 5″ Kodachrome transparency by Alfred Palmer)

The B-25 was powered by two air-cooled, supercharged, 2,603.737-cubic-inch-displacement (42.688 liter) Wright Aeronautical Division Cyclone 14 GR2600B665 (R-2600-9) two-row 14-cylinder radial engines which were rated at 1,500 horsepower at 2,400 r.p.m., and 1,700 horsepower at 2,600 r.p.m. for takeoff. These engines (also commonly called “Twin Cyclone”) drove three-bladed Hamilton Standard Hydromatic variable-pitch propellers through 16:9 gear reduction. The R-2600-9 was 5 feet, 3.1 inches (1.603 meters) long and 4 feet, 6.26 inches (1.378 meters) in diameter. It weighed 1,980 pounds (898 kilograms).

The medium bomber had a maximum speed of 322 miles per hour (518 kilometers per hour) at 15,000 feet (4,572 meters) and a service ceiling of 30,000 feet (9,144 meters). It could carry a 3,000 pound bomb load 2,000 miles (3,219 kilometers).

Defensive armament consisted of three air-cooled Browning M2 .30-caliber aircraft machine guns and one Browning AN-M2 .50-caliber machine gun.

After testing was completed, B-25 40-2165 was retained by North American and modified as a company transport. On 8 January 1945, flown by Edgar A. Stewart, the airplane suffered an engine failure and made a forced landing at Mines Field—the location of its first flight. The prototype B-25 was damaged beyond repair.

Front view of the first North American B-25 Mitchell, 40-2165. The constant dihedral wing was used on the first nine airplanes built. (U.S. Air Force) — Front view of the first North American Aviation B-25 Mitchell medium bomber, 40-2165, at Mines Field, August 1940. The constant dihedral wing was used on the first nine airplanes built. (U.S. Air Force)

North American B-25 — North American Aviation NA-62, B-25 Mitchell 40-2165, left front. (U.S. Air Force)

North American B-25 Mitchell 40-2165, left rear. (U.S. Air Force) — North American Aviation B-25 Mitchell 40-2165, left rear. (U.S. Air Force)

North American Aviation B-25A Mitchell twin-engine medium bomber in flight near Wright Field, Ohio, 1 May 1941. (Rudy Arnold Photo Collection, Smithsonian Institution National Air and Space Museum XRA-4945)

¹ The wing center section of the B-25H and B-25J has 4° 38′ 23″ dihedral. The outer sections have 0° 21′ 39″. The wing has 2° 29′ 37″ negative twist.

6 August 1945

August 6, 2023Aviation44-85048, Ace, Ace of Aces, Aircraft Accident, Browning Machine Gun Caliber .50 AN-M2, Dick Bong, Fighter Pilot, Lockheed Air Terminal, Lockheed Aircraft Company, Lockheed P-80A-1-LO Shooting Star, Medal of Honor, North Hollywood, Richard Ira Bong, Test PilotBryan Swopes

Bong, Richard Ira, Major, United States Army Air Forces. (United States Air Force 160506-D-LN615-001) — Major Richard Ira Bong, United States Army Air Forces. (U.S. Air Force)

6 August 1945: After serving three combat tours flying the Lockheed P-38 Lightning in the Southwest Pacific, Major Richard Ira Bong, Air Corps, United States Army, was assigned as an Air Force acceptance test pilot for new Lockheed P-80 Shooting Star jet fighters at the Lockheed Air Terminal, Burbank, California.

The P-80A was a brand new jet fighter, and Major Bong had flown just 4 hours, 15 minutes in the type during 12 flights.

Shortly after takeoff in P-80A-1-LO 44-85048, the primary fuel pump for the turbojet engine failed. A back-up fuel pump was not turned on. The Shooting Star rolled upside down and Bong bailed out, but he was too low for his parachute to open and he was killed. The jet crashed at the intersection of Oxnard Street and Satsuma Avenue, North Hollywood, California, and exploded.

Site of the crash of Major Richard I. Bong’s Lockheed P-80A-1-LO fighter, 44-85048, at Oxnard Street and Satsuma Avenue, North Hollywood, California. (Contemporary news photograph)

This graphic appeared in the Los Angles Times, 7 August 1945, at Page 3. (Los Angeles Times)

General Douglas MacArthur with Major Richard I. Bong.

Richard I. Bong was known as the “Ace of Aces” for scoring 40 aerial victories over Japanese airplanes between 27 December 1942 and 17 December 1944 while flying the Lockheed P-38 Lightning. He was awarded the Medal of Honor, which was presented by General Douglas MacArthur, 12 December 1944. [The following day, General MacArthur was promoted to General of the Army.]

The citation for Major Bong’s Medal of Honor reads: “For conspicuous gallantry and intrepidity in action above and beyond the call of duty in the Southwest Pacific area from 10 October to 15 November 1944. Though assigned to duty as gunnery instructor and neither required nor expected to perform combat duty, Major Bong voluntarily and at his own urgent request engaged in repeated combat missions, including unusually hazardous sorties over Balikpapan, Borneo, and in the Leyte area of the Philippines. His aggressiveness and daring resulted in his shooting down eight enemy airplanes during this period.”

General of the Army Henry H. (“Hap”) Arnold and Major Richard I. Bong, circa 1945.

The Lockheed P-80-1-LO was the United States’ first operational jet fighter. It was a single-seat, single-engine low-wing monoplane powered by a turbojet engine. The fighter was designed by a team of engineers led by Clarence L. (“Kelly”) Johnson. The prototype XP-80A, 44-83020, nicknamed Lulu-Belle, was first flown by test pilot Tony LeVier at Muroc Army Air Field (now known as Edwards Air Force Base), 8 January 1944.

Lockheed P-80A-1-LO shooting Star 44-85004, similar to the fighter being test flown by Richard I. Bong, 6 August 1945. (U.S. Air Force)

The P-80A was a day fighter, and was not equipped for night or all-weather combat operations. The P-80A was 34 feet, 6 inches (10.516 meters) long with a wingspan of 38 feet, 10.5037 inches (11.84919 meters) ¹ and overall height of 11 feet, 4 inches (3.454 meters).

The leading edges of the P-80A’s wings were swept aft 9° 18′ 33″. They had an angle of incidence of +1° at the root and -0° 30′ at the tip. There was 3° 50′ dihedral. The total wing area was 237.70 square feet (22.083 square meters).

The fighter had an empty weight of 7,920 pounds (3,592 kilograms) and a gross weight of 11,700 pounds (5,307 kilograms). The maximum takeoff weight was 14,000 pounds (6,350 kilograms).

Lockheed P-80 Shooting Star production, alongside P-38 Lightnings. (SDASM)

Early production P-80As were powered by either an Allison J33-A-9 or a General Electric J33-GE-11 turbojet engine. The J33 was a licensed version of the Rolls-Royce Derwent. It was a single-shaft turbojet with a 1-stage centrifugal compressor section and a 1-stage axial-flow turbine. The -9 and -11 engines were rated at 3,825 pounds of thrust (17.014 kilonewtons). The J33s were 8 feet, 6.9 inches (2.614 meters) long, 4 feet, 2.5 inches (1.283 meters) in diameter and weighed 1,775 pounds (805 kilograms).

The P-80A had a cruising speed of 445 miles per hour (716 kilometers per hour) at 20,000 feet (6,096 meters). Its maximum speed was 548 miles per hour (882 kilometers per hour) at 2,700 feet (823 meters) and and 501 miles per hour (806 kilometers per hour) at 34,700 feet (10,577 meters).² The service ceiling was 45,000 feet (13,716 meters).

Lockheed P-80A-1-LO Shooting Star 44-85155, similar to the jet fighter which Major Bong was flying, 6 August 1945. (U.S. Air Force)

The P-80A Shooting Star was armed with six air-cooled Browning AN-M2 .50-caliber aircraft machine guns mounted in the nose.

Dick Bong poses with “Marge,” his Lockheed P-38J Lightning. A large photograph of his fiancee, Miss Marjorie Vattendahl, is glued to the fighter’s nose.

¹ Wing span with rounded wing tips. P-80As with squared (“clipped”) tips had a wing span of 37 feet, 7.5037 inches (11.46819 meters).

² Several hundred of the early production P-80 Shooting stars had all of their surface seams filled, and the airplanes were primed and painted. Although this process added 60 pounds (27.2 kilograms) to the empty weight, the decrease in drag allowed a 10 mile per hour (16 kilometers per hour) increase in top speed. The painted surface was difficult to maintain in the field and the process was discontinued.

31 July 1923: Browning Machine Gun, Caliber .50, AN-M2

July 31, 2023Aviation.50 BMG, Aircraft Machine Gun, Browning Machine Gun Caliber .50 AN-M2, Heavy Machine Gun, John Moses Browing, Patent No. 1628226Bryan Swopes

This photograph shows SSGT Maynard H. Smith with a Browning .50-caliber machine gun at the left waist position of a B-17 Flying Fortress. (U.S. Air Force)

31 July 1923: The original patent application, Serial No. 654,955, for the legendary Browning .50-caliber machine gun was filed with the United States Patent Office on 31 July 1923. Patent Number 1,628,226 was issued to the estate of John Moses Browning by the Patent Office on 10 May 1927.

The majority of United States combat aircraft during World War II were armed with the Browning Machine Gun, Caliber .50, AN-M2. The machine gun could be mounted as a fixed weapon in the aircraft’s wings or nose, in flexible mounts, or power-operated turrets.

Three Browning .50-caliber machine guns and belted ammunition installed in the left wing of a Vought-Sikorsky F4U-1 Corsair, 11 August 1942. (Vought-Sikorsky)

The basic aircraft Browning machine gun, cal. .50, AN-M2. . . is an automatic, recoil-operated, belt-fed, air-cooled machine gun. The metallic link disintegrating belt is used in all firing of the gun. The gun is designed for all cal. .50 aircraft machine gun installations. By properly repositioning some of the component parts, ammunition may be fed into the gun from either the right or the left side.

—TM9-225 War Department Technical Manual, BROWNING MACHINE GUN, CALIBER .50, AN-M2, AIRCRAFT, BASIC, 28 January 1947, Section II., Paragraph 3. General, at Page 2

Illustration of the basic .50-caliber Browning machine gun, AN-M2. (War Department)

The Browning Machine Gun (“BMG”) was designed by John Moses Browning, who had also designed the Automatic Pistol, Caliber .45, M1911, the standard sidearm of the U.S. military for 74 years; the Rifle, Caliber .30, Automatic, Browning, M1918 (best known as the “Browning Automatic Rifle” or “BAR”); the Browning Machine Gun, Caliber .30, M1919; and the Browning Hi-Power, a 9 × 19 mm double-action semiautomatic pistol designed for Fabrique National (FN) of Herstal, Belgium.

The AN-M2 aircraft machine gun has an overall length of 56.25 inches (1.429 meters) and weighs 61.00 pounds (27.67 kilograms). The barrel is cylindrical, and 36.00 inches (0.91 meters) long. It is surrounded by a barrel jacket with ventilation holes to dissipate heat. The bore has 8 rifled-grooves with a right-hand twist, making one complete turn in every 15.00 inches (0.381 meters).

John Browning with a water-cooled version of his .50-caliber machine gun. (Museums at Union Station/The Wall Street Journal)

The basic AN-M2 gun could be modified to be manually fired with the substitution of a “spade grip” back plate. It could also be changed from left-hand ammunition feed to right hand by reversing some internal parts.

The M2 machine gun had a rate of fire of 750 to 850 rounds per minute.

Armorers load disintegrating-link belts of .50-caliber ammunition for the eight machine guns of a Republic P-47 Thunderbolt. (U.S. Air Force)

Ammunition is ball, armor-piercing, armor-piercing-incendiary, tracer, blank (no bullet), and dummy. The armor-piercing cartridge, M2, has a muzzle velocity of 2,840 feet per second (866 meters per second) and maximum range of 7,275 yards (6,652 meters). Some .50-caliber rounds have muzzle velocities as high as 3,450 feet per second (1,052 meters per second), though most range from 2,730 fps to 2,900 fps (832–884 m/s). The ammunition produces chamber pressures of approximately 55,000 pounds per square inch (3,792 bar).

A gunner fires the two Browning .50-caliber machine guns of a B-17’s ball turret. (U.S. Air Force)

The .50 BMG cartridge is 5.45 inches (13.843 centimeters) long (NATO 12.7 × 99). The rimless, tapered bottleneck case is 3.91 inches (9.931 centimeters) long, with diameters of 0.560 inches (14.224 millimeters) at the neck, 0.735 inches (18.669 millimeters) at the shoulder, and 0.804 inches (20.422 millimeters) at the base. The bullet is 2.31 inches (58.67 millimeters) long, with a maximum diameter of 0.510 inches (12.954 millimeters) and weighs 706.7 grains (1.6 ounces, 45.8 grams).

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